Solvent-free hydration of alkynes over Hβ zeolite

Mameda, Naresh; Swamy, Peraka; Reddy, Marri Mahender; Kodumuri, Srujana; Chevella, Durgaiah; Gutta, Naresh; Narender, Nama

doi:10.1016/j.apcata.2015.07.038

Cited by 20 publications

(4 citation statements)

References 31 publications

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“…While the acid H 3 [PMo 12 O 40 ] ⋅ n H 2 O 9 a afforded essentially the E ‐stereoisomer, the corresponding silver derivative Ag 3 [PMo 12 O 40 ] ⋅ n H 2 O 9 b gave mostly the Z ‐isomeric enones [12] . On the other hand, Hβ zeolite was also able to perform MSR in water at 100 °C, affording three examples of cinnamaldehyde derivatives [13] . Finally, in refluxing toluene and in the presence of acidic alumina, propargylic alcohols and 2‐thionaphthol reacted together in a cascade process to give directly the thioacetal of the enal obtained after MSR [14] …”

Section: New Catalytic Systems Leading To αβ‐Unsaturated Carbonyl Dementioning

confidence: 99%

Recent Developments in the Meyer‐Schuster Rearrangement

Justaud¹,

Hachem

Grée³

2021

Eur J Org Chem

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Most of this review article has been prepared during Covid 19 pandemy. Therefore, we dedicate it,-first to all persons who unfortunately died from this disease and,-second to all people (medical doctors and many others) who helped their congeners to survive to this pandemy. The Meyer-Schuster rearrangement is an efficient method to prepare α,β-unsatured carbonyl compounds starting from propargylic alcohols and this review presents the remarkable progress made during the last decade in this reaction. New efficient catalytic systems have been discovered and many elegant applications have been reported for this rearrangement. To be noticed in particular are the new and efficient cascade processes affording a wide range of carbo-and heterocyclic molecules. Moreover, brilliant applications of this rearrangement have been described as well, in the total synthesis of complex natural products and their analogues. Finally, the first examples of aza-Meyer-Schuster rearrangements have been recently described as well.

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Section: New Catalytic Systems Leading To αβ‐Unsaturated Carbonyl Dementioning

confidence: 99%

Recent Developments in the Meyer‐Schuster Rearrangement

Justaud¹,

Hachem

Grée³

2021

Eur J Org Chem

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“…In research focused on the hydration of alkynes, Nama proposed using Hβ zeolite, a microporous aluminosilicate, as an efficient and environmentally friendly catalytic system to achieve this transformation (Scheme 14). 37 The authors found that hydration reactions occurred with a α-regioselectivity and that zeolite Hβ exhibited excellent catalytic activity and could be reused after simple filtration.…”

Section: Hydration Of Arylalkylalkynesmentioning

confidence: 99%

Hydration of Unsymmetrical Internal Alkynes: Factors Governing the Regioselectivity

et al. 2023

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Water addition on an unsymmetrical internal alkyne has significance in organic chemistry and has stimulated challenging approaches to access a highly regioselective process. Hydration or formal hydration is presented according to the type of internal alkyne. Methods for electron-rich and -poor diarylalkynes followed by those adapted to arylalkylalkynes are presented. Regioselective hydration reactions of unsymmetrical propargylic and homopropargylic derivatives are then discussed, followed by regioselective aspects of the hydration of internal alkynes directed by carbonyl groups. The following section examines the hydration alkynes linked to CF 3 , esters, ketones, and heteroatoms as haloalkynes, alkynylphosphonates, ynamides, and others. At the end of this section, we report some recent examples of hydration reactions where the alkyne triple bond is connected to an electron-withdrawing group as an ester or a ketone. Reactions are presented, discussed, and illustrated in each of these items through various representative examples. The mechanistic hypotheses explaining the origin of the regioselectivity in the hydration reactions are discussed. This review of recent advances in the regioselective hydration of internal unsymmetrical alkynes (from 2007 until the present) aims to update the current body of knowledge and aid researchers working in this field.

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“…Conventionally, this reaction is carried out in the presence of a large number of acidic reagents and highly toxic additives such as mercury(II) salts and mercury(II) oxide. , Hence, several homogeneous catalysts have been developed to replace these toxic reagents. − Although these catalysts efficiently convert various alkynes to the corresponding ketones, they suffer from several drawbacks including the use of high-cost noble metals, requirement of additives such as ligands, and problems in separation and reusability of the catalyst. To overcome these issues heterogeneous catalysts including graphene oxide, tin–tungsten mixed oxide, Au-NHC@porous organic polymers, silver-exchanged silicotungstic acid catalyst, polymer-based solid acids, Hβ zeolites, , and poly(ionic liquid)s solid acids have been developed recently. Some of these catalysts such as tin–tungsten mixed oxide have shown excellent catalytic activities toward alkyne hydration.…”

Section: Introductionmentioning

confidence: 99%

Mesoporous Crystalline Niobium Oxide with a High Surface Area: A Solid Acid Catalyst for Alkyne Hydration

Rathnayake

Perera

Shirazi-Amin

et al. 2020

ACS Appl. Mater. Interfaces

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A mesoporous crystalline niobium oxide with tunable pore sizes was synthesized via the sol–gel-based inverse micelle method. The material shows a surface area of 127 m2/g, which is the highest surface area reported so far for crystalline niobium oxide synthesized by soft template methods. The material also has a monomodal pore size distribution with an average pore diameter of 5.6 nm. A comprehensive characterization of niobium oxide was performed using powder X-ray diffraction, Brunauer–Emmett–Teller, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, UV–vis, and X-ray photoelectron spectroscopy. The material acts as an environmentally friendly, solid acid catalyst toward hydration of alkynes under with excellent catalytic activity (99% conversion, 99% selectivity, and 4.39 h–1 TOF). Brønsted acid sites present in the catalyst were found to be responsible for the high catalytic activity. The catalyst was reusable up to five cycles without a significant loss of the activity.

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Solvent-free hydration of alkynes over Hβ zeolite

Cited by 20 publications

References 31 publications

Recent Developments in the Meyer‐Schuster Rearrangement

Recent Developments in the Meyer‐Schuster Rearrangement

Hydration of Unsymmetrical Internal Alkynes: Factors Governing the Regioselectivity

Mesoporous Crystalline Niobium Oxide with a High Surface Area: A Solid Acid Catalyst for Alkyne Hydration

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